In the

temporal bone The temporal bone is a paired bone situated at the sides and base of the skull, lateral to the temporal lobe of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples where four of the cranial bone ...

, between the posterior wall of the

external acoustic meatus The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the auricle to the eardrum and is about in length and in diameter. Str ...

and the posterior root of the

zygomatic process The zygomatic processes (aka. malar) are three processes (protrusions) from other bones of the skull which each articulate with the zygomatic bone. The three processes are: * Zygomatic process of frontal bone from the frontal bone * Zygomatic ...

is the area called the suprameatal triangle, suprameatal pit, mastoid fossa, foveola suprameatica, or

Macewen MacEwen, MacEwan, McEwen, or McEwan may refer to: People * MacEwen (surname) Places * Castle MacEwen, Argyll, Scotland *MacEwan, Edmonton, a neighbourhood in Edmonton, Alberta, Canada * MacEwan Glen, a neighbourhood in Calgary, Alberta, Canada ...

's triangle, through which an instrument may be pushed into the

mastoid antrum The mastoid antrum (tympanic antrum, antrum mastoideum, Valsalva's antrum) is an air space in the petrous portion of the temporal bone, communicating posteriorly with the mastoid cells and anteriorly with the epitympanic recess of the middle ear ...

.
In the adult, the antrum lies approximately 1.5 to 2 cm deep to the suprameatal triangle. This is an important landmark when performing a cortical mastoidectomy. The triangle lies deep to the cymba conchae.

References

Bones of the head and neck {{musculoskeletal-stub